One method taught by the prior art to load a camera involves first placing a cartridge that contains a filmstrip and a protruding film leader in a chamber and then threading the leader end onto a take-up spool. Typically, the take-up spool has a gear driven mechanism that engages initial sprocket holes in the leader. Some people have difficulty loading the camera. As a result, a camera was developed that utilizes a threadless cartridge. An example of a threadless cartridge is Kodak 126 film cartridge. This is relatively large because it has a take-up spool and a take-up chamber.
Other types of cartridges that contain filmstrips have been developed. Some of the cartridges do not contain take-up chambers and take-up spools. One cartridge contains an internal mechanism to thrust the film leader out of the cartridge. This cartridge can be placed in a camera by a procedure called "shot-gun loading." The shot-gun loading procedure involves opening a film door covering a chamber in the camera, and simply dropping the cartridge into the chamber.
A camera that utilizes shot-gun loading may require the camera to be turned up side down in order for the cartridge to be loaded into the camera. This is considered to be cumbersome.
Another method of shod-gun loading a camera is called "four bin loading". Flour bin loading permits a photographer to load and unload a cartridge without turning the camera upside down. See U.S. Pat. Nos. 5,105,211, issued Apr. 14, 1992, and 4,363,547, issued Dec. 14, 1982.